H̊akan Källberg - Consultant

Q: Where is H̊akan based?

H̊akan is based in Ladenburg, Germany .

Q: What languages does H̊akan speak?

H̊akan speaks the following languages: German (Native), Swedish (Native), English (Advanced), Spanish (Elementary), French (Elementary) .

Q: How many years of experience does H̊akan have?

H̊akan has at least 29 years of experience. During this time, H̊akan has worked in at least 2 different roles and for 5 different companies . The average length of individual experience is 1 year and 10 months . Note that H̊akan may not have shared all experience and actually has more experience.

Q: What is H̊akan's latest experience?

H̊akan's most recent position is Consultant at Simulina GmbH .

Q: What companies has H̊akan worked for in recent years?

In recent years, H̊akan has worked for Simulina GmbH .

Q: Which industries is H̊akan most experienced in?

H̊akan is most experienced in industries like Information Technology (IT) , Retail , and Telecommunication . H̊akan also has some experience in Professional Services , Banking and Finance , and Energy .

Q: Which business areas is H̊akan most experienced in?

H̊akan is most experienced in business areas like Information Technology (IT) , Operations , and Product Development . H̊akan also has some experience in Customer Service , Finance , and Research and Development (R&D) .

Q: Which industries has H̊akan worked in recently?

H̊akan has recently worked in industries like Retail , Information Technology (IT) , and Professional Services .

Q: Which business areas has H̊akan worked in recently?

H̊akan has recently worked in business areas like Information Technology (IT) , Operations , and Customer Service .

Recommended expert

Ladenburg, Germany

Experience

Jan 2024 - Present

2 years 3 months

Ladenburg, Germany

Consultant

Simulina GmbH

Project planning of photovoltaic systems for a citizens' initiative
Design of billing systems

Feb 2022 - Oct 2023

1 year 9 months

Darmstadt, Germany

Consultant

Simulina GmbH

Migration of a distributed application to new hardware on Linux, Solaris, and AIX
Porting OpenSolaris tools to Linux
Using Universal Packet Manager and EPM for packaging across different architectures
Shell script programming
Use of GitLab

Jan 2022 - Apr 2022

4 months

Königsbach-Stein, Germany

Consultant

Simulina GmbH

Development of a web application for billing charging sessions in an EV charging station park
Management of charging stations, users, and RFID cards
Implementation using Python/Django on a Raspberry Pi

Sep 2021 - Dec 2021

4 months

Weiterstadt, Germany

Consultant

Simulina GmbH

Testing dial-in solutions in a carrier environment
Test automation with RobotFramework
Network testing with Scapy
Use of Git, GitLab, Debian, Jira in a Scrum environment

May 2021 - Jul 2021

3 months

Bremen, Germany

Consultant

Simulina GmbH

Porting from Python 2 to Python 3
Use of Git, GitLab, and Debian in the Scrum process

Jul 2019 - Feb 2020

8 months

Vienna, Austria

Consultant

Simulina GmbH

Developed a gateway for the TALQ Smart City protocol on Digi embedded computers
Established communication via the WirePas mesh network protocol and the REST-based TALQ protocol
Implemented in Python 3 with Twisted

Jan 2019 - Jun 2019

6 months

Stuttgart, Germany

Consultant

Simulina GmbH

Created a REST interface for data forwarding over sockets to an Unreal server
Planned a WebSocket interface
Programmed in Python
Used Git with Bitbucket and Jira

May 2018 - Oct 2018

6 months

Düsseldorf, Germany

Consultant

Simulina GmbH

Developed a QR code reader app with Python TK (tkinter)
Connected to the dcTrack backend system via a JSON-based REST API
Packaged in Python
Performed usage analysis of QR codes

Jan 2018 - Mar 2018

3 months

Düsseldorf, Germany

Consultant

Simulina GmbH

Programmed and designed APIs using Django REST framework
Created an API to manage nameserver data
Evaluated Flask, Twisted, and SQLAlchemy as alternatives

Dec 2016 - Apr 2017

5 months

Frankfurt, Germany

Consultant

Simulina GmbH

Connected mobile laptops with encrypted file systems
Installed VS-NfD systems with VPN connections
Set up Secunet SINA workstations and SINA smart cards
Developed small Python and Bash scripts

Jan 2013 - Mar 2016

3 years 3 months

Garmisch-Partenkirchen, Germany

Consultant

Simulina GmbH

Supported the eGap research project in Garmisch-Partenkirchen in the field of e-mobility
Co-developed a multi-tenant e-mobility platform as a business-as-a-service
Connected charging stations via LyconSys routers using OpenVPN behind firewalls and UMTS routers
Communicated via REST-based web services and integrated external geo services
Used Python, Bash, MySQL, PHP
Programmed charging station controllers on embedded Linux devices in Python
Displayed real-time charging data with Crossbar and microservices
Phone-based activation using SIP-Gate and Asterisk server

Sep 2012 - Dec 2012

4 months

Stuttgart, Germany

Consultant

Simulina GmbH

Managed email and domains with Postfix and Bind
Wrote scripts in Perl, Python, and Bash
Introduced Git as a repository

Feb 2010 - Jul 2012

2 years 6 months

Schriesheim, Germany

Consultant

Simulina GmbH

Collaborated on the FutureFleet research project in e-mobility
Developed charging management software for electric cars in Python
Web programming and data exchange using PHP and MySQL
Designed architecture with REST APIs and XML/XSD, later adding JSON interfaces

Jul 2009 - Jan 2010

7 months

Frankfurt, Germany

Consultant

Simulina GmbH

Software development on the LyconSys router platform (embedded Linux)
Shell scripting, software packaging, and web programming

May 2009 - Jun 2009

2 months

Germany

Consultant

Simulina GmbH

Developed in C on AIX
Adapted existing RADIUS tools for IPv6

Jan 2009 - Present

17 years 3 months

Consultant

Simulina GmbH

Creation of a membership management system for a sports club
Implementation of a mailing list management system in PHP/MySQL/Perl
Expansion into a multi-tenant solution

Jan 2008 - Present

18 years 3 months

Sweden

Consultant

Simulina GmbH

Setup of a call center based on Asterisk

May 2007 - Apr 2009

2 years

Germany

Consultant

Simulina GmbH

Testing customer-specific DHCP and RADIUS software on AIX
Scripting and log analysis with Perl

Mar 2007 - Present

19 years 1 month

Germany

Consultant

Simulina GmbH

Setup of eGroupWare with LDAP as a contact database for VoIP phones (Snom)

Jan 2007 - Feb 2007

2 months

Consultant

Simulina GmbH

Development of a call center agent application with LAMP
Perl CGI scripts for Excel export and import

Dec 2006 - Present

19 years 4 months

Consultant

Simulina GmbH

Built a server rack with a switch, Astaro firewall, UPS, and a Linux-based SAMBA/Intranet server

Nov 2006 - Present

19 years 5 months

Consultant

Simulina GmbH

Installed and commissioned an Astaro firewall with a VPN link

Oct 2006 - Present

19 years 6 months

Consultant

Simulina GmbH

Set up a Zarafa Outlook server on Linux/MySQL

Jan 2006 - Dec 2006

1 year

Consultant

Simulina GmbH

Developed multiple Asterisk-based PBX systems worldwide

Jul 2004 - Jul 2011

7 years 1 month

Consultant

Simulina GmbH

Implemented VoIP solutions with Cisco and Asterisk VoIP servers over ISDN-PRI
Integrated IP PBX systems and installed VoIP phones

Mar 2004 - Present

22 years 1 month

Consultant

Simulina GmbH

Preparation and delivery of a technician training on s390 Linux, zSeries

Jan 2004 - Dec 2004

1 year

Consultant

Simulina GmbH

Definition and implementation of firewall, VPN, and mail concepts for the public sector and SMEs
Installation and setup of mail systems with spam control (SPF, greylisting)

Jan 2003 - Dec 2004

2 years

Consultant

Simulina GmbH

Setup of various web hosting environments on Linux and Solaris platforms

Jan 2003 - Dec 2003

1 year

Consultant

Simulina GmbH

Webmaster role for a brokerage group
Creation of an automated billing system for web transactions

Jan 2002 - Present

24 years 3 months

Consultant

Simulina GmbH

Conceptual and security analysis at a trading company including firewall consulting and installations on Linux, Solaris, and Cisco

Jan 2002 - Dec 2002

1 year

Frankfurt, Germany

Developer

Reuters AG

Modification of an application for Reuters on Solaris in C/C++
Integration of license management and additional calculation functions

Jan 2000 - Dec 2002

3 years

Developer

Telekurs AG

Development of an interface for securities master data import into the SAP Treasury System
Use of WebMethods, Perl, and XML/DTD

Jan 1999 - Dec 2000

2 years

Frankfurt, Germany

Developer

Commerzbank AG

Development of a disaster recovery tool for mirroring data centers
Programming in Perl with Sybase database
Platforms: Sun E10k, Brocade SAN, EMC Symmetrix

Jan 1997 - Dec 1999

3 years

Developer

SAP/Reuters

Interface programming for SAP Treasury for real-time import of Reuters market data
Use of Solaris, C++, and Triarch SSL

Industries Experience

See where this freelancer has spent most of their professional time. Longer bars indicate deeper hands-on experience, while shorter ones reflect targeted or project-based work.

Experienced in Information Technology (26 years), Retail (24 years), Telecommunication (21.5 years), Professional Services (19.5 years), Banking and Finance (6 years), and Energy (5.5 years).

Information Technology

Retail

Telecommunication

Professional Services

Banking and Finance

Energy

Business Areas Experience

The graph below provides a cumulative view of the freelancer's experience across multiple business areas, calculated from completed and active engagements. It highlights the areas where the freelancer has most frequently contributed to planning, execution, and delivery of business outcomes.

Experienced in Information Technology (29 years), Operations (19.5 years), Product Development (19 years), Customer Service (18.5 years), Finance (3 years), and Research and Development (2.5 years).

Information Technology

Operations

Product Development

Customer Service

Finance

Research and Development

Skills

Backend Programming
Software Engineering, Backend Programming/scripting
Rest Apis
Interface Programming/apis
Websockets Microservices
It Consulting
Consulting For Solar Power Systems And E-mobility
Project Management
Voip - Call Centers, Pbx, Asterisk
Security, Firewalls, Network Management
Mail And Web Solutions
Mail Server/groupware: Postfix, Egroupware, Zarafa
Client/server And Storage Consolidation
Installation And Integration
System Administration - Focus On Networks/linux/solaris
Individual Training
It Experience Since: 1983
Hardware: Sun Hardware
Cisco Routers And Switches
Lyconsys Routers
Operating Systems: Linux (Especially Suse)
Solaris
Development Tools: Python (Twisted, Django)
Microservices: Wamp/websockets, Crossbar/autobahn
Xml/xsd - Json
Perl
C++/c
Php
Simula 67
Subversion, Git, Gitlab
Databases: Mysql/mariadb
Postgresql
Sybase
Mongodb
Database Interfaces: Python
Perl/dbi
Sql
Odbc
Network Knowledge: Tcp/ip
Intranet/internet/apache
Ethernet
Firewalls - E.g. Astaro, Ip Filter
Snmp
Wlan, Vlan
Openvpn
Ipsec, Ipv6
Voip, Asterisk, Pbx Systems
Cisco Ios
Groupware/crm: Egroupware, Zarafa, Owncloud, Nextcloud ...
Sugar Crm
Tcp/ip-based Services (Smtp/mail - Postfix, Imap, Ftp, News, Dns, Nfs, Nis/nis+, Samba, Www/http, Ssh, Ssl, Voip, Etc.)
Client/server Programming
Shell Programming (Sh, Bash, Csh/tcsh, Ksh, Perl, Python)
Transaction Systems, Data Import, Export, Conversion
Porting And Migration Of Existing Applications To The Target Unix Platform (C/c++)
Storage, Raid, Lvm, Backup
Linux Ha
Customization, Extension, And Enhancement Of System-level Software
Computer-based Documentation Systems (Tex, Latex, Postscript, Pdf, Html, Groff, Markdown)
System V Packaging
Linux (Rpm) Packaging

Languages

German

Native

Swedish

Native

English

Advanced

Spanish

Elementary

French

Elementary

Education

Chalmers University of Technology

Physics, Computer Science · Gothenburg, Sweden

Profile

Created

October 2025

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Frequently asked questions

Do you have questions? Here you can find further information.

Where is H̊akan based?

H̊akan is based in Ladenburg, Germany.

What languages does H̊akan speak?

H̊akan speaks the following languages: German (Native), Swedish (Native), English (Advanced), Spanish (Elementary), French (Elementary).

How many years of experience does H̊akan have?

H̊akan has at least 29 years of experience. During this time, H̊akan has worked in at least 2 different roles and for 5 different companies. The average length of individual experience is 1 year and 10 months. Note that H̊akan may not have shared all experience and actually has more experience.

What roles would H̊akan be best suited for?

Based on recent experience, H̊akan would be well-suited for roles such as: Consultant, Developer.

What is H̊akan's latest experience?

H̊akan's most recent position is Consultant at Simulina GmbH.

What companies has H̊akan worked for in recent years?

In recent years, H̊akan has worked for Simulina GmbH.

Which industries is H̊akan most experienced in?

H̊akan is most experienced in industries like Information Technology (IT), Retail, and Telecommunication. H̊akan also has some experience in Professional Services, Banking and Finance, and Energy.

Which business areas is H̊akan most experienced in?

H̊akan is most experienced in business areas like Information Technology (IT), Operations, and Product Development. H̊akan also has some experience in Customer Service, Finance, and Research and Development (R&D).

Which industries has H̊akan worked in recently?

H̊akan has recently worked in industries like Retail, Information Technology (IT), and Professional Services.

Which business areas has H̊akan worked in recently?

H̊akan has recently worked in business areas like Information Technology (IT), Operations, and Customer Service.

What is H̊akan's education?

H̊akan attended Chalmers University of Technology for Physics, Computer Science.

What is the availability of H̊akan?

H̊akan is immediately available for suitable projects.

What is the rate of H̊akan?

H̊akan's rate depends on the specific project requirements. Please use the Meet button on the profile to schedule a meeting and discuss the details.